Bound slave is made to cum by a fucking machine and her Mistress

Mistress has left her slave in a very precarious position. The woman is bound on her back with her legs spread, a fucking machine pistoning a dildo in and out of her pussy at a constant rate. If left alone, it would fuck her pussy for hours and hours, never tiring. The mean Mistress clips clothespins all over the slave’s body, from her perky tits down to her shaved pussy. The domme flicks and tugs on them until they come off, and their removal seems to prove even more painful than when they were attached. The machine is finally turned off, showing that her pussy is absolutely soaked from the constant deep fucking. Her Mistress then uses a vibrator on her, driving her even wilder with pleasure. She fucks faster and harder until the slave finally cums, screaming out in ecstasy after all the teasing and pain. But the dominatrix isn’t done, returning with a stronger vibrator to make her cum again, apparently aiming to make her go crazy from the excessive stimulation.